Aircraft systems such as environmental control systems and wing anti-ice systems require hot air for proper operation. Typically, the hot air is provided by an engine of the aircraft by extraction from a compressor of the engine. The extracted air is then routed to the aircraft systems in need.
The extraction of air from the compressor negatively impacts the engine performance since the extracted air is not used to generate thrust. Such impact becomes more and more important since trends in engine design are oriented toward an increase of the bypass ratio. The core flow thus becomes smaller, but the different systems still require the same quantity of hot air.